1. Field of the Disclosure
This disclosure generally relates to a switch device and, more particularly, to a capacitive switch that may increase the detection accuracy by employing a reference circuit.
2. Description of the Related Art
Conventionally, the switch device uses a mechanical switch to detect the press of a user or the on/off status. However, the conventional mechanical switch may appear poor response due to poor electrical contact or failure due to elastic fatigue of the element after frequent operation.
Therefore, the industry proposed the capacitive switch that can detect the capacitance variation caused by a touch, e.g. detecting the variation of oscillation frequency or charging duration, to accordingly identify whether a touch event occurs or not. However, the electrical deviation may be generated in the conventional capacitance detection circuit due to the variation of manufacturing process, operating voltage and temperature such that misidentification may occur during operation thereby decreasing the operation accuracy.
Accordingly, the present disclosure further provides a capacitive switch whose detection results are compared with the output of a reference circuit so as to eliminate the electrical deviation caused by factors of the manufacturing process and operating environment thereby achieving higher detection accuracy.